Where to go from here?

That KRELL K-300i is an awesome integrated. The internal DAC is good, and if you desire can upgrade later to an external DAC. You can get close to Mola Mola Tamabqui sound for much, much less. Spending a lot of DAC helps the audio industry and the economy keep moving. However, your ears you likely will be OK with something in the $1500-$3000 range (my ears are). 

A super neutral $719 Topping D90LE mates well with the warm K-300i. In my opinion, the Toppng D90SE (or LE), Benchmark DAC3B, Musetec 005 are better than the internal DAC. The internal DAC is not bad, just that the others that are good matches for the K-300i.

I still always recommend the internal DAC in the K-300i because it is good enough and it has HDMI which is great on that unit. The ROON READY on the K-300i is the very best I have ever used. It has volume adjustment from the ROON Client app. I do not know of any other unit that can do that.

@jjss49

Good catch, I incorrectly assumed that the speaker were either bookshelf or floorstanders.

@davekuyt11
Speaker placement, a trial and error exercise, is extremely important in high end audio and necessary to get the great 3D soundstage. Room treatments usually happen after placement of speakers to tame unwanted reflections and bass energy. In high end audio, everything in the audio chain matters. The lack of ability for optimal speaker placement is a glaring weak chain link.

Are you assembling an analog and/or a digital system?

Digital only. I mostly stream qobuz. I use a transport for a few cds some of the time. I can add krell to the list. How is  the bolder 866? If one pops up used that could be another made in america integrated to add to mcintosh and krell.

Going back to  ghdprentice's comment. His opinion was that the streamer was possibly the most important. In that case I need to audition a lumin x1 or p1. Reviews claim that the leedh volume is as good as a preamp. Its dac looks to be very good. I see used x1 in the  7-8000 range. The new p1 would get me ht bypass. I could then save up to get the lumin amp later. Their amp has high impedance input to work well with leedh direct to amp. The amp sure is pricey tho. 

Streamer: Innuos Zen and Zenith very popular/safe option.